/**
 * 合并相同数据，导出合并列所需的方法(只适合el-table)
 * @param {Object} data
 * @param {Object} rowspanArray
 */
export function getRowspanMethod(data, rowspanArray) {

  /**
   * 要合并列的数据
   */
  const rowspanNumObject = {};

  //初始化 rowspanNumObject
  rowspanArray.map(item => {
    rowspanNumObject[item] = new Array(data.length).fill(1, 0, 1).fill(0, 1);
    rowspanNumObject[`${item}-index`] = 0;
  });
  //计算相关的合并信息
  for (let i = 1; i < data.length; i++) {
    rowspanArray.map(key => {
      const index = rowspanNumObject[`${key}-index`];
      if (data[i][key] === data[i - 1][key] && data[i]['g0accessmonth'] === data[i - 1]['g0accessmonth']) {
        rowspanNumObject[key][index]++;
      } else {
        rowspanNumObject[`${key}-index`] = i;
        rowspanNumObject[key][i] = 1;
      }
    });
  }

  //提供合并的方法并导出
  const spanMethod = function ({
    row,
    column,
    rowIndex,
    columnIndex
  }) {
    if (rowspanArray.includes(column['property'])) {
      const rowspan = rowspanNumObject[column['property']][rowIndex];
      if (rowspan > 0) {
        return {
          rowspan: rowspan,
          colspan: 1
        }
      }
      return {
        rowspan: 0,
        colspan: 0
      }
    }
    return {
      rowspan: 1,
      colspan: 1
    }
  };

  return spanMethod;
}